Insect repellents



Patented Feb. 5, 1952 s PATENT ""orrica U ITED- m re INSECT REPELLENTS Paul D. Bartlett, Weston, McKusick, Wilmington,

Mass., and Blaine 0. Del., assignors to the United States of America as represented by the Secretary of the Army No Drawing. Application January 7, 1949,

Serial No.

6 Claims.

, 1 This invention relates to insect repellents. We havediscovered that the application of a dialkyl ester of hexahydrophthalic acid, having the structural formula H2 1120 E01] R wherein R is an alkyl radical preferably having a Insect Bepellency upon Application to Skin i g o mpregna e Material Am) he! Fabric against Aedes g- Ades aem pti aegz pti Z culatus Mina. Minx. acid, dimethyl ester 256 66 over 10 days. acid, diethyl ester (cis)..- 194 55 over 10 days.

diethyl ester (trans). 206 57 at least 1 day. acid, di-n-propyl ester. over 60 acid, di-i-propyl ester over 60 over 10 days. acid, dx-i-amyl ester over 60 Not determined.

not more than 2 carbon atoms, when applied to the human skin or a fabric, effectively repels insects, particularly Aedes aegypti and Anopheles quadrim vaculat us.

Tests to measure the repellency of the abovementioned compounds against insects by skin application were conducted by smearing the compound on the arms of test personnel, who then thrust their arms into cages containing insects. The arms were exposed for -minute intervals at 3 minutes each until the first insect bite.

Tests to measure the repellency of fabrics impregnated with the above-mentioned compounds against insects were conducted by uniformly impregnating mercerized cotton hose'with the compound at a rate equivalent to 3.3 gms. per sq. ft., drawing the dried hose over the arms of test personnel, who then thrust their covered arms into cages containing insects for l to 2 50 mi te It will be seen from the foregoing table that the dimethyl and diethyl esters of hexahydrophthalic acid possess superior insect repellent properties, while the insect repellent properties of the corresponding propyl and higher esters are not particularly striking.

For ease of application, the hexaphydrophthalic acid esters contemplated by the present invention may be incorporated in a suitable inert liquid or solid carrier such as mineral oil, alcohol, petrolatum, etc. For facile and uniform fabric impregnation, they may be applied in an inert solvent, such as alcohol, ether, etc.

Having thus fully described our invention, we claim:

1. An insect-repellent fabric comprising fabric impregnated with dimethyl-hexaphydrophthal ate.

2. An insect-repellent composition comprising dimethyl-hexahydrophthalate in an inert nongeseous organic carrier.

3. An insect repellent composition comprising UNITED STATES PATENTS dimethyl-hexahydrophtha1ate in alcohol. Number Name Date 4. An insect repellent composition comprising 2,400,006 Jones et a1 May 7, 1946 dimethyl-hexahydrophthalate in ether.

5. An insect repellent composition comprising 5 OTHER REFERENCES dimethyl-hexahydrophthalate in oil. 0. S. R. D.: Committee on Medical Research.

6. An-, insect repellent composition comprising August 31, 1945, page 17, Progress Report No. 25, dimethyl-hexahydrophthalate in petrolatum. section 1. (Copy available in Div. 43) PAUL D. BARTLETT. p Linduska et aL: Flea Repellents for .Use on BLAINE C. McKUSICK. Clothing. Journal of Economic Entomology. December 1946,pp.'767+769. w REFERENCES CITED The following references are of record in the file of this patent: 

2. AN INSERT-REPELLENT COMPOSITION COMPRISING DIMETHYL-HEXAHYDROPHTHALATE IN AN INERT NONGASEOUS ORGANIC CARRIER. 